In recent years, documents used in organizations have been increasingly created and stored as electronic data. Such trend has been accelerated by the storage cost reduction, increased awareness of the internal control, and expansion of the advantages of electronic data (e.g., can be stored at low cost and can be shared easily) with the progress of computer technology.
As the technologies for displaying files in a tiered folder with a tree structure managed by a file system, the following has been developed and provided so far.
1) Existing Technology 1: dir command of Windows (registered trademark) or ls command of Unix (registered trademark): files in a specific folder are listed.
2) Existing Technology 2: tree command and explorer of Windows(registered trademark): A folder tier structure is displayed in a tree structure. With the explorer, it is possible to display subfolders of a specified holder, and not display substructures of the other folders.
3) Existing Technology 3: Disk-space display software: Software that displays the tiers of a folder and the sum of the file size in the folder has been developed. Examples of such software include Scanner, WinDu2, WinDirStat, SequoiaView, and SpaceMonger (Non-Patent Documents 1 to 5). Such software has the object of visually determining what kind of files occupy the great part of the disk space and finding and deleting unnecessary, large-size files to efficiently obtain a disk free space.
4) Existing Technology 4: Document search: documents that contain a character string specified as a query by a user are listed. “Google Search Appliance” (Non-Patent Document 6) provided by Google Inc. has a function of highlight-displaying a query character string contained in documents. “Velocity” (Non-Patent Document 7) provided by Vivisimo has a function of, when a plurality of documents that contains a query is found, dynamically classifying the documents by the fields of the documents, and displaying the results.
5) Existing Technology 5: As a document management system, a document management system that uses a user interface imitating a bookshelf and binders has been provided (Non-Patent Document 8). This system has a function of sorting stored documents into binders by the kinds of the documents and permitting comment writing by use of labels.    Non-Patent Document 1: Scanner: http://www.steffengerlach.de/freeware/    Non-Patent Document 2: WinDu2:http://www.vectorco.jp/soft/win95/util/se059546.html    Non-Patent Document 3: WinDirStat: http://windirstat.sourceforge.net/    Non-Patent Document 4: SequoiaView: http://w3.win.tue.nl/nl/onderzoek/onderzoek_informatica/visualization/sequoiaview    Non-Patent Document 5: SpaceMonger: http://www.sixty-five.cc/sm/    Non-Patent Document 6: Google Search Appliance: http://www.google.co.jp/enterprise/gsa/    Non-Patent Document 7: Velocity: http://vivisimo.com/html/products    Non-Patent Document 8: Visual Cabinet (NEC Corporation): http://www.nec.co.jp/univerge/solution/pack/visual_cabinet/index.html    Non-Patent Document 9: Rack-Rack Library (PFU LIMITED): http://www.pafujitsu.com/raku2library/